1. Field of the Invention
The present invention relates to a liquid crystal indication device or a liquid crystal panel used for a shutter array, etc used for a printer head, and more particularly to a ferroelectric liquid crystal panel using a ferroelectric liquid crystal.
2. Description of the Prior Art
A liquid crystal panel using a ferroelectric liquid crystal, known in the prior art, comprises a liquid crystal cell containing a liquid crystal sealed between, for example, 2 glass substrates like a liquid crystal panel using an ordinary nematic liquid crustal, and is operated as a display panel or an optical shutter by applying a driving voltage across transparent electrodes equipped inside the glass substrates. However, the ferroelectric liquid crystal has a high dielectric constant and is different from a nematic liquid crystal in that it is driven by DC (Direct Current) for turning ON and OFF according the direction (positive or negative) of an electric field applied. In addition, the voltage-transmittance characteristics thereof are not completely known. Therefore, for displaying the panel in an intermediate tone. It is required to vary the ON/OFF ratio at high response speed or altering the area ratio of ON/OFF.
One of the drawbacks associated with the driving a ferroelectric liquid crystal panel with DC as described above, is that it tends to cause premature deterioration of the liquid crystal cell when it is used to display intermediate tones. This premature deterioration manifests itself by causing the display pixels to vary in brightness. In addition, the pixels deteriorate irregularly, resulting in the difficulty of driving the panel stably.